Counting mechanism



June 21; 1949- NAMl-:NYl-KATZ 2,474,156

COUNTING MECHANISM.

June 21,1949. Ll NAMENY|-KATZ 2,474,156 L COUNTING MECHANISM Filed April 5, 1945 2 sheets-sheet 2 HVENTQK RTTOME YS lassociated therewith, and means Patented `lune 21, 1949 COUNTING MECHANISM Laszlo N amenyi-Katz, London, England, assignor of one-half to Furzehill Laboratories Limited, Boreham Wood, England Application April 3, 1945, Serial No. 586,333 In Great Britain December 23, 1943 This invention relates to apparatus actuatedy by the passage of articles through it, such as banknotes, for example, for the purpose of counting the articles, or for operating other mechanism in response to the passage of the articles.

According to this invention, an apparatus actuated by the passage of an article through it comprises means for generating a field of energy in the ether which is capable of being disturbed by the presence of the article therein, means for traversing the article through said eld and means responsive to the disturbance of the iieid, which means are arranged to control counting and/ or indicating apparatus.

In the case of an apparatus for actuation by banknotes having metal strips therein, such apparatus comprises means responsive to the presence of such strips, means for feeding said notes past the responsive means, and means operable by the responses set up for or counting apparatus.

Means may be provided for generating an electric or magnetic field through which said banknotes are traversed whereby an impulse is set up in said generating means, and means are pro- .vided for indicating or counting the number of impulses and/or their amplitude. Means may be provided for integrating the amplitude and duration of said disturbances.

The means for generating the aforesaid field of energy may comprise an inductance arranged in an oscillatory circuit, means for traversing articles past said inductance, whereby its value is altered and an impulse is set up in the circuit and counting said impulses.

The aforesaid inductance may be arranged in one limb of an electric bridge and a power supply is connected across one diagonal of the bridge, while means are provided for applying the relsulting potential across the second diagonal to a circuit controlling indicating or counting means.

In one form of construction, a variable inductance is arranged with the first said inductso controlled by a ance in said bridge and is follow-up device responsive to the resulting potential across the second diagonal as to tend electrically to balance said bridge, which followlup device is larranged also to control the aforementioned indicating or counting means. A source of alternating supply may be connected across one diagonal of the bridge, while a valve amplifier is connected across the other diagonal,

and the aforesaid variable inductance may comprise a reactor valve circuit which reactor valve actuating indicating for indicating f 11 Claims. (Cl. 23S-92) is so energised from control means associated with said amplifier as also to constitute said follow-up device whereby the inductance value of the reactor valve is brought to a value which tends to balance the bridge, and means are provided for feeding the indicating and/or counting means with a voltage proportional to that fed to the input of the reactor valve.

The control means may comprise a balanced modulator fed both with a carrier from said source of alternating supply and with the output from said amplier, so that a D. C. output is obtained from the balanced modulator, which reverses in sign as the bridge ouput goes through the balance point.

The aforesaid reactor valve may be connected vin parallel with the inductance, which produces gain of the amplier does not adversely affect the operation of the apparatus.

The following is a description of one form of the apparatus for use with a banknote counting device according to the invention, reference being made to the accompanying drawing, in which:

Figure 1 is a circuit diagram of the apparatus,

Figures 2 to 5 show the form of impulses provided by the apparatus according to how the notes are fed through it,

Figure 6 is a block diagram of a reactor valve unit and the wiring connections associated therewith,

Figure '7 is a similar diagram of an integrator device, and

Figure 8 is a diagram of a discharge device, indicated diagrammatically in Figure 1 of the drawings.

Referring to Figure l, the apparatus comprises an alternating current bridge, having resistors 4 and 5 and inductors. 2 and 3. The bridge is fed across one diagonal with a source of alternating E. M. F., I, by leads 3|, 32, at an appropriate frequency. The input of an amplifier 6 is connected across the other diagonal by leads I5, It, in such a manner that this amplifier amplies the out-ofbalance voltage of the bridge. The output of the amplifier is connected to a balanced modulator 1, by leads I'I, I8, which is also supplied by leads I3, I4, with a signal input derived from the A. C. source I. The output from the balanced modulator which feeds the leads I9, 20, is D. C., and its magnitude is substantially proportional to the out-of-balance voltage of the bridge and its sign depends on the direction of the out-of-balance,

according to whether the cross product of arms 3, 4, is greater than the cross product of arms 2, 5, or vice versa. The output of the balanced modulator 1 is fed to a reactor valve unit 8 of known kind by leads I9, 28.

The unit 8 includes the reactor valve 34 as a thermionic valve having a cathode connected to a negative H. T. supply, an anode 36 connected through a suitable de-coupling resistance 31 to a positive H. T. supply and a control grid 38. The cathode and anode of this valve are connected across the inductance 3 through a suitable condenser 39 and the grid and cathode of the Valve are connected to the conductors I9 and `20 so that the D. C. potential or bias of the grid 38 is derived from the modulator 1. A resistance 40 is interposed between the grid 38 and the 4conductor I9 and the grid is coupled to the plate by means of capacity 4I so that the grid receives an A. C. feed back potential through the plate circuit in phase quadrature with the alternating potential across the inductance 3. The effect of this arrangement is that the valve 34 functions as an inductance connected across the inductance 3 and having an inductance value which is variable in dependence upon the D. C. voltage applied to the grid 38 from the modulator 1. The valve 34 may be of any type having a characteristic such that the variations of grid potential supplied from the conductor I9 vary the mutual conductance of the valve and thus vary the reactance effect obtained by the feed-back through the capacity 4I. The input from the modulator 1 is amplified by the valve 34 and applied across the conductors 23, 24 through a high-frequency choke 42 or equivalent device which transmits the low frequency amplified potential variations from the plate of the valve 34 to the conductor 24 whilst substantially isolating the conductor 2.4 from the high frequency potential variations applied to the plate of the valve 34 through the conductor 2 l.

Leads 2l, 22 are so connected to the reactor valve as to make use of its characteristics of an inductance whose value depends upon the Voltage input derived from the balanced modulator 1. The inductance value is not reversible about the point of zero linput voltage, but will continue to change in inductance in the same direction as the voltage input passes through zero. The reactor valve 8 is connected across the bridge arm 3 by leads 2|, 22.

The direction of connections of all the apparatus so far described is such that any unbalanced voltage produced by the bridge will be amplified and applied to the reactor vvalve so as to cause .an inductance change to .arm 3 of the bridge, which will tend to cause the bridge to re-balance The reason for this effect is as follows: Suppose the bridge to have been balanced, whereafter the arm 3 is changed by a small amount L, this will produce an unbalance voltage E soithat Er-RL where lc is a constant of proportionality. Assume the value of the signal voltage is V and this produces an inductance change of -H in such a fashion that -H =1 .V. where p is the constant of proportionality of the reactor valve. As indicated above, the bridge tends to re-balance. The original lchange .in arm r3 of L will now have been reduced to L-H.. The unbalanced voltage caused by this will be k(L-H) and the signal input to the balanced modulator uK (L-H) where u is the effective gain of the amplifier and modulator system. Now thisvmust produce the compensating inductance chan-ge of -H which obviously can be written as puk (L-H). The condition of the system is given by -H=puk (L-H). Now provided the factor pak is much greater than unity, L=H, L can be made as near equal to H as required by making the factor pula large enough. It will be noted that each of these factors is, in a sense, a sensitivity factor and each operates in a fashion when large to apply the greatest re-balancing effect to the bridge.

From the foregoing description it is clear that if puk is made large enough any change of inductance that is caused to occur to arm 3 will be almost completely nullified by a similar change of inductance to the reactor valve 8.

Now since L=H and VzH/p, V=L/p. In other words, the voltage derived at the input to the reactor valve 8 is nearly proportional to the original inductance change in arm 3. The design of reactance valve 8 is such that the factor p is of high stability so that the voltage V is always closely proportional to the inductance change in arm 3. It should be noted that, whereas the factor p is required to be stable the actual value 4of the other factors ku have no great influence on the performance of the device, providing the product of the factors loup is large. Any change in the value of K or lu only make 2nd order differences to the relation between V and L.

In practice, this means that neither the magnitude of the voltage applied to the bridge nor the gain of the amplifier `are in any way critical. It should be noted that the foregoing analysis is descriptive rather `than rigorous and is given to show in what manner the device operates and not as a mathematical treatment.

Means 33 are provided for passing the banknotes shown in dotted lines in Fig. l to be counted in such a fashion that the metal strips pass through the field of inductance 3. As shown in Figure 1, the banknote is being passed endwise through the machine, and thus the embedded metallic strips, which extend across the short dimension of the banknote, move through the counting device in a position transverse to the direction of the feeding movement. A measure of the disturbance is available in the form of a voltage at the input to the reactor valve, as already explained. Provided the notes pass only one at a time and are .spaced such that one metal strip clears the field of the coil before another enters it the voltage V may be used to operate a counter without difficulty. Furthermore, if the notes, due to imperfections in the mechanical arrangements, are liable to pass in packets of a small number at a time and with the strips at the same end of the note and substantially superimposed it would be possible again to use the voltage available at the input to the reactor valve, which will be substantially proportional to the number of notes in each packet, to operate a discriminating counter which is responsive to the size of the impulse.

On the other hand, if notes pass through the field with 'the strips not in alignment'which is the condition envisaged in the apparatus being described, other means must be adopted to produce a voltage which bears such a relation to the num- 'ber'of notes passing that'it can be used to .operate a counter indicating 'this number.

The means hereinafter described which are used'to overcome this difficulty .are provided vto pass the notes across the field of the coil at a fixed speed and to construct atime integral of the disturbance produced. Figure 2 shows the form of 'the voltage produced by a single note passing through the field of the coil. Figures 3 and 4 show the form of the voltage produced by the pas- Aand 3 notes, in which the second packet is out of alignment.

Now considering again the circuit of Figure 1 a voltage proportional to the input to the reactor valve is fed into an integrating device 9 by leads 23y 24. This integrating device has as its essentials a resistance feeding into a condenser. The integrator shown in Figure 7 of the drawings comprises a resistance 52 connected in series with a condenser 53 across the input 23, 24. The resistance 52 and condenser 53 constitute an integrating circuit which has a long time constant as compared with the time period of the impulses received by the integrator. When, therefore, these impulses are applied as a variable voltage across the conductors 24, 23 the potential across the condenser 53 varies as the time integral of the disturbances produced. The condenser 53 is connected by the leads 25 and 26 to the discharging device l by which the condenser is discharged when the signal inputfalls to zero. The voltage across the condenser constitutes the output of the integrator and the voltage at this point (leads 25, 26) will thus be proportional to the area of the curves, shown in Figures 2 to 5. It is plain that the integral of voltage produced in Figures 3 and 4, for instance, will be substantially similar. In other words, a means has been found for producing the same effect from a number 0f notes in close alignment and a number of notes close together but not in alignment. As so far described, the integrator would continue to summate the number of notes, whether in packets or not, indefinitely, and in fact it is possible to make the device operate in this fashion for a small number of notes. In the instrument being described, however, the integrator condenser is arranged to be discharged after each multiple or single impulse. This is effected by the discharging device I0 connected to the integrator by leads 25, 26 and operated from a proportion or function of the integrator input signal and connected by leads 2l, 2li so that the integrator is discharged whenever the signal input falls to zero. For instance, in Figure 5, the integrator would be discharged at points marked A, B and C.

The discharged device lll is illustrated in Figure 8 and comprises a gas discharge valve 43 having its plate electrode connected to the conductor 25 and its cathode connected to the conductor 26. The conductor 28 is connected to the cathode of the valve 43 and the conductor 21 (which is continuous Iwith the conductor 24 and is thus connected to the plate of the valve 34) is connected to the grid thereof, through a suitable biasing device represented at 44 in Figure 8 which is adjusted so that the potential applied to the grid of the valve 43 when the valve 34 receives no signal from the modulator 'l is just sufficient to iire the valve 43. During the reception of signals, the plate of the valve 34 lbecomes more negative with the result that the grid of the valve 43 is biased negatively so that the valve 43 is non-conductive. When the signal falls to zero, the potential of the grid 43 rises to a suiiicient positive value to lire the valve and discharge the condenser 53.

In the device ybeing described allowance has been made only to count continuous impulses caused by up to a maximum number of 3 notes, it being considered that the mechanical arrangements feeding the notes will never allow more 'fili than 3 notes to Eo through more or less together.

The counter II which is connected to the integrator by leads 29, 30 and which is described in detail in United States Patent application Serial No. 586,332, led Apr. 3, 1945, is operated by means of relays so that it will discriminate between unit, double and treble size impulses and operate accordingly.

I claim:

1. An apparatus actuated by the insertion or passage of articles, comprising means for generating a eld of energy in the ether which is capable of being disturbed by the presence of an article therein, means for traversing the articles separately or together through said field whereby impulses are set up in said generating means, and means for indicating the number of articles passing through said eld comprising indicating means responsive to the number of impulses and their amplitude.

2. An apparatus of the class described adapted to be actuated by the presence of bank notes having metal strips therein, said apparatus comprising means for generating a eld of energy, said generating means being responsive to the presence of said strips, means for feeding said bank notes with the strips transverse to the direction of feeding movement past said responsive means, and means for counting said bank notes operably responsive to the number of the responses set up in the eld by the passage of said bank notes and to their amplitude.

3. Apparatus for counting articles comprising means for traversing said articles at constant speed through a counting station, electrical impulse producing means for producing an electrical impulse when an article passes said station and integrating means for integrating the amplitude and duration of said impulses so as to produce an integrated signal having an amplitude proportional to the number of articles which have passed through said head.

fl. Apparatus for counting articles comprising vmeans for traversing said articles through a counting station, electrical impulse producing means located at said station for producing an electrical impulse when an article passes said station and an integrating device comprising a long time-constant circuit comprising a resistance and a condenser for producing across said condenser a voltage proportional to the number of articles passed through said counting station.

5. Apparatus for counting articles comprising an electrical inductance element, means for traversing said articles through the field of said inductance element, means for electrically energising said inductance element, means responsive to variations in the inductance value of said inductance element for producing electrical signals proportional to said variations in inductance value, a long time constant circuit comprising a resistance and capacit for integrating said signals whereby there is produced across said capacity a signal voltage proportional to the number of articles passed through the field of said inductance element and means for applying said signals to said circuit.

6. An apparatus of the class described adapted to be actuated by the insertion or passage of an article, comprising, in combination, means for generating a eld of energy in the ether which is capable of being disturbed by the presence of an article therein, said means being an inductance arranged in an oscillatory circuit, means .resulting across for traversing articles past said inductance whereby its value is altered and an impulse is set up in said circuit, and means forv indicating said impulses, said inductance being arranged to form one limb of an electric bridge, a power supply arranged across one diagonal o-f said bridge, means for applying the potential resulting across the second diagonal to a circuit controlling said indicating means, which circuit includes a variable inductance in said bridge associated with the rst said inductance and a follow-up device controlling said variable inductance so as electrically to balance said bridge and also controlling said indicating means.

7. An apparatus accordingto claim 6, wherein said power source consists of an alternating supply and said means for applying the potential the second diagonal consists of a valve amplifier, and wherein said variable inductance comprises a reactor valve so energized from control means associated with said amplier as to constitute said follow-up device whereby the reactor valve inductance is brought to a value which balances the bridge and wherein means are provided feeding the indicating means with a voltage proportional to that fed to the input of the reactor valve.

8. An apparatus according to claim 6, wherein said power source consists of an alternating supply and said means for applying the potential resulting across the second diagonal consists of a valve ampliiier, and wherein said variable inductance comprises a reactor valve so energized from control means associated with said ampli- Iier as to constitute said follow-up device whereby the reactor valve inductance is brought to a value which balances the bridge and wherein means are provided feeding the indicating means with a Voltage proportional to that fed to the input of the reactor valve, said control means comprising a balanced modulator fed with a carrier from' said source of alternating supply and with an output from said amplifier, so that a D. C. output is obtained which reverses in sign as the bridge output goes through the balance point.

9. An apparatus according to claim 6, wherein said power source consists of an alternating supply and said means for applying the potential resulting across the second diagonal consists of a valve amplifier, and wherein said variable inductance comprises a reactor valve so energized from control means associated with said amplifier as to constitute said follow-up device whereby the reactor valve inductance is brought to a Value which balances the bridge and wherein means are provided feeding the indicating means with a voltage proportional to that fed to the input of the reactor valve, said control means comprising a balanced modulator fed with a carrier from said source of alternating supply and with an output from said amplier, so that a D. C. output is obtained which reverses in sign as the bridge output goes through the balance point, said reactor valve being connected in parallel with the inductance which produces the aforesaid iield of energy.

10. An apparatus according to claim 6, wherein said power source consists of an alternating supply and said means for applying the potential across the second diagonal consists of a valve amplifier and wherein said variable inductance comprises a reactor valve so energized from control means associated with said amplifier as to constiute said follow-up device whereby the reactor valve inductance is brought to a value which tends to balance the bridge and wherein means are provided feeding the indicating means with a voltage proportional to that fed to the input of the reactor valve and, wherein said voltage proportional to that fed to the input of the reactor valve is fed to means for producing an output Voltage dependent on the time integral of the input voltage, which output voltage is applied to the indicating means.

11. An apparatus according to claim 6, wherein said power source consists of an alternating supply and said means for applying the potential across the second diagonal consists of a valve amplifier' and wherein said variable inductance comprises a reactor valve so energized from control means associated with said amplifier as to constitute said followup device whereby the reactor valve inductance is brought to a value which tends to oalance the bridge and wherein means are provided feeding the indicating means with a voltage proportional to that fed to the input of the reactor valve and, wherein said voltage proportional to that fed to the input of the reactor Valve is fed to means for producing an output voltage dependent on the time integral of the input voltage, which output voltage is applied to the indicating means, and wherein said electrical integrating means is of the resistance and condenser type and wherein a discharging device is associated with said condenser and is so controlled by the input to the reactor valve that a discharge takes place when the signal input falls to zero.

LASZLO NAMENYLKATZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,708,524 Tatz Apr. 9, 1929 1,797,651 Gergacsevics et al. Mar. 24, 1931 1,957,222 Mershon May 1, 1934 2,905,892 Gulliksen June 25, 1935 2,228,068 White Jan. 7, 1941 2,251,973 Beale et al. Aug. 12, 1941 2,337,132 Shaw Dec. 21, 1943 2,402,222 Willis June 18, 1946 

